No one has come up with a valid strategy that would have worked better than what we have been doing. If we did nothing in Iraq and focused all of our attention on Afghanistan, what would be different? We are a tiny Army, as far as soldiers on the ground. We don't have the man power to take out every terrorist. There would just be more soldiers to protect poppy fields. The Soviets tried that type of warfare on Afghanistan and lost.
It makes no sense to send a Heavy Mechanized Brigade to Afghanistan. They are useless. That is why Bush/Cheney/Rumsfeld changed the army to be more mobile. Creating BCT's and switching some Heavy (tank) brigades to Strykers, which can be used in Iraq, Afghanistan, and others. Right now the only units going to Afghanistan have been light Inf brigades. Our Army, before Rumsfeld, was set up for cold war fighting with a huge amount towards tanks and artillery units.